Electrophotographic sensitive materials containing disazo compounds

Abstract

The present invention provides electrophotographic sensitive materials having a high sensitivity as well as a high flexibility which comprise a conductive support and a photosensitive layer formed thereon, said photosensitive layer containing one disazo pigment, as an effective ingredient, which is selected from the group consisting of disazo pigments expressed by the following general formulas I, II, III, and IV, ##STR1## [(wherein A is selected from the group consisting of ##STR2## is selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc., hetero rings such as indole ring, carbazole ring, benzofuran ring, etc. and their substituents, Ar 1 is selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc., hetero rings such as dibenzofuran, etc. and their substituents, Ar 2 and Ar 3 are selected from the group consisting of aromatic rings such as benzene ring, naphthalene ring, etc. and their substituents, R 1 and R 3 are selected from the group consisting of hydrogen, lower alkyl radical or phenyl radical and their substituents and R 2 is selected from the group consisting of lower alkyl radical, carboxyl radical and their esters)].

What is claimed is: 
     
       1. An electrophotographic material having a high sensitivity as well as a high flexibility, which comprises an electrically conductive support and a photosensitive layer formed thereon, said photosensitive layer consisting essentially of fine particles of disazo pigment selected from the group consisting of disazo pigments having the formulas I and III, ##STR19## wherein A is selected from the group consisting of ##STR20## is a fused ring selected from the group consisting of benzene ring, halobenzene ring, naphthalene ring, indole ring, carbazole ring and benzofuran ring; Ar 1  is a member selected from the group consisting of phenyl, methylphenyl, methoxyphenyl, chlorophenyl, nitrophenyl, ethoxyphenyl, methylchlorophenyl, dimethylphenyl, methoxychlorophenyl, methoxybromophenyl, methoxymethylphenyl, dimethoxyphenyl, dimethoxychlorophenyl, dimethylaminophenyl, cyanophenyl, carboxyphenyl, benzenesulfonic acid sodium salt, tert-butoxyphenyl, naphthyl, methoxydibenzofuryl and carbazolyl; each of Ar 2  and Ar 3  is a member selected from the group consisting of phenyl, naphthyl, methoxyphenyl, methylphenyl, acetylaminophenyl, dimethylaminophenyl, cyanophenyl, nitrophenyl, dinitrophenyl, chlorophenyl, trichlorobenzenesulfonic acid, benzenesulfonic acid and benzenesulfonamide; each of R 1  and R 3  is a member selected from the group consisting of hydrogen, methyl, ethyl, phenyl and chlorophenyl; and R 2  is a member selected from the group consisting of methyl, carboxyl and --COOC 2  H 5  ; and a resinous binder. 
     
     
       2. An electrophotographic material according to claim 1 wherein the particle size of said disazo pigment is less than 5 microns, the amount of said disazo pigment is 30-70%, based on the weight of the photosensitive layer, and the thickness of the photosensitive layer is about 3 to 50 microns. 
     
     
       3. An electrophotographic material according to claim 1 in which A is ##STR21## 
     
     
       4. An electrophotographic material according to claim 1 in which A is ##STR22## 
     
     
       5. An electrophotographic material which comprises an electrically conductive support and a photosensitive layer formed thereon, said photosensitive layer consisting essentially of fine particles of disazo pigment selected from the group consisting of disazo pigments having the formulas I and III, ##STR23## wherein A is selected from the group consisting of ##STR24## is a fused ring selected from the group consisting of benzene ring, halobenzene ring, naphthalene ring, indole ring, carbazole ring and benzofuran ring; Ar 1  is a member selected from the group consisting of phenyl, methylphenyl, methoxyphenyl, chlorophenyl, nitrophenyl, ethoxyphenyl, methylchlorophenyl, dimethylphenyl, methoxychlorophenyl, methoxybromophenyl, methoxymethylphenyl, dimethoxyphenyl, dimethoxychlorophenyl, dimethylaminophenyl, cyanophenyl, carboxyphenyl, benzenesulfonic acid sodium salt, tert-butoxyphenyl, naphthyl, methoxydibenzofuryl and carbazolyl; each of Ar 2  and Ar 3  is a member selected from the group consisting of phenyl, naphthyl, methoxyphenyl, methylphenyl, acetylaminophenyl, dimethylaminophenyl, cyanophenyl, nitrophenyl, dinitrophenyl, chlorophenyl, trichlorobenzenesulfonic acid, benzenesulfonic acid and benzenesulfonamide; each of R 1  and R 3  is a member selected from the group consisting of hydrogen, methyl, ethyl, phenyl and chlorophenyl; and R 2  is a member selected from the group consisting of methyl, carboxyl and --COOC 2  H 5  ; a charge-transfer substance and a resinous binder. 
     
     
       6. An electrophotographic material according to claim 5 wherein the particle size of said disazo pigment is less than 5 microns, the amount of said disazo pigment is 1-50% and the amount of said charge-transfer substance is 10-95%, based on the weight of the photosensitive layer, and the thickness of the photosensitive layer is about 3 to 50 microns. 
     
     
       7. An electrophotographic material according to claim 5 in which A is ##STR25## 
     
     
       8. An electrophotograhic material according to claim 5 in which A is ##STR26## 
     
     
       9. An electrophotographic material which comprises an electrically conductive support and a charge carrier-generating layer formed thereon, said charge carrier-generating layer consisting essentially of fine particles of disazo pigment selected from the group consisting of disazo pigments having the formulas I and III, ##STR27## wherein A is selected from the group consisting of ##STR28## is a fused ring selected from the group consisting of benzene ring, halobenzene ring, naphthalene ring, indole ring, cabazole ring and benzofuran ring; Ar 1  is a member selected from the group consisting of phenyl, methylphenyl, methoxyphenyl, chlorophenyl, nitrophenyl, ethoxyphenyl, methylchlorophenyl, dimethylphenyl, methoxychlorophenyl, methoxybromophenyl, methoxymethylphenyl, dimethoxyphenyl, dimethoxychlorophenyl, dimethylaminophenyl, cyanophenyl, carboxyphenyl, benzenesulfonic acid sodium salt, tert-butoxyphenyl, naphthyl, methoxydibenzofuryl and carbazolyl; each of Ar 2  and Ar 3  is a member selected from the group consisting of phenyl, naphthyl, methoxyphenyl, methylphenyl, acetylaminophenyl, dimethylaminophenyl, cyanophenyl, nitrophenyl, dinitrophenyl, chlorophenyl, trichlorobenzenesulfonic acid, benzenesulfonic acid and benzenesulfonamide; each of R 1  and R 3  is a member selected from the group consisting of hydrogen, methyl, ethyl, phenyl and chlorophenyl; and R 2  is a member selected from the group consisting of methyl, carboxyl and --COOC 2  H 5  ; and a charge-transfer layer on said charge-carrier generating layer, said charge-transfer layer consisting essentially of a charge-transfer substance and a resinous binder. 
     
     
       10. An electrophotographic material according to claim 9 wherein the particle size of said disazo pigment is less than 5 microns, the amount of said charge-transfer substance is 10-95%, based on the weight of said charge-transfer layer, the thickness of said charge carrier-generating layer is less than 5 microns and the thickness of said charge-transfer layer is about 3 to 50 microns. 
     
     
       11. An electrophotograhic material according to claim 10 in which A is ##STR29## 
     
     
       12. An electrophotographic material according to claim 10 in which A is ##STR30## 
     
     
       13. An electrophotographic material which comprises an electrically conductive support, a charge-transfer layer on said support, said charge-transfer layer consisting essentially of a charge-transfer substance and a resinous binder, and a charge carrier-generating layer on said charge-transfer layer, said charge carrier-generating layer consisting essentially of fine particles of disazo pigment selected from the group consisting of disazo pigments having the formulas I and III, ##STR31## wherein A is selected from the group consisting of ##STR32## is a fused ring selected from the group consisting of benzene ring, halobenzene ring, naphthalene ring, indole ring, carbazole ring and benzofuran ring; Ar 1  is a member selected from the group consisting of phenyl, methylphenyl, methoxyphenyl, chlorophenyl, nitrophenyl, ethoxyphenyl, methylchlorophenyl, dimethylphenyl, methoxychlorophenyl, methoxybromophenyl, methoxymethylphenyl, dimethoxyphenyl, dimethoxychlorophenyl, dimethylaminophenyl, cyanophenyl, carboxyphenyl, benzenesulfonic acid sodium salt, tert-butoxyphenyl, naphthyl, methoxydibenzofuryl and carbazolyl; each of Ar 2  and Ar 3  is a member selected from the group consisting of phenyl, naphthyl, methoxyphenyl, methylphenyl, acetylaminophenyl, dimethylaminophenyl, cyanophenyl, nitrophenyl, dinitrophenyl, chlorophenyl, trichlorobenzenesulfonic acid, benzenesulfonic acid and benzenesulfonamide; each of R 1  and R 3  is a member selected from the group consisting of hydrogen, methyl, ethyl, phenyl and chlorophenyl; and R 2  is a member selected from the group consisting of methyl, carboxyl and --COOC 2  H 5 . 
     
     
       14. An electrophotograhic material according to claim 13 wherein the particle size of said disazo pigment is less than 5 microns, and the amount of said charge-transfer substance is 10-95% by weight, based on the weight of said charge-transfer layer, the thickness of said charge carrier-generating layer is less than 5 microns and the thickness of said charge-transfer layer is about 3 to 50 microns. 
     
     
       15. An electrophotographic material according to claim 13 in which A is ##STR33## 
     
     
       16. An electrophotographic material according to claim 13 in which A is ##STR34##